Relay.



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a 'fr Wmviiiij UNITED sTATEs PATENT oEEIoE.

ARCHIBALD-S. CUBITT, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

RELAY.

Specication'o! Letters Patent.

Patented Apn'i 21, 1908.

Apgumion med auguri 24., 1907. seriu No. 880,081.

To all 'whom 'it may concern:

Be it known that I, ARCHIBALD S. CUnI'r'r, a subject of the King of Great Britain, residing at Schenectady, county of Schenectady, State of New York, have invented certaln new and useful Improvements in Relays, of which the followinl is aspecification. e

My invention reates to relays, and particularly to that form of relay in which two coils are employed, one being an actuating coil of few turns of a heavy conductor, and the other a coil of many turns of finer Wire.

Relays of this kind are often used in connection with motor control -apparatus of the' separatelyv actuated contact type and serve to protect the a paratus against overload. In such service t e heavyconductor of few turns generally' carries the main motor current, while the other coil of smaller wire receivescurrent, after the relay has pulled up, through contacts closed by the relay, and through contacts closed when the masterswitch is in anyT but its ofl or first position. The main contacts of the relay may be connected in thetmain control circuit, or ma be case, pulling nip of the relay allows all the 30 ft e contactors o controller to drop, thereby opening the motor circuit, and in the second case, operationof the relay allows only the resistance` controlling contactors 'to drop, thereby throwing all the resistance into the motor circuit but not breaking the connection of the motors with the source. of curl lrent. Such a relay, if the current in the motor circuit exceeds a certain value, is coilV conductor and few turns and is.

ulled u gf hea p then he d in its raised position by the other coil until the master-switch is thrown to its off orfrst position. y

In relays of this type where the current in the actuating coil is large, the field produced by it' may be sufficiently strong if it is given but a singleturn. When still higher currents are to be handled, even one turn in this coil may produce too strongI a field and it becomes necessary to wea en 1t 1n some way.

by the field produced by the It is at once obvious that when this coil has been reduced to a single turn it is difiicplty to arrange the conductor so that the magnetic field produced byit will be materially weaker than that produced by a single-turn.

The iron frame 6 of the It is an obect of m invention to provide means where y the e ective magnetic field, produced by the actuating coil, may be easily regulated when the current in this coil is so high that the field normally produced by a single turn would be stronger than is desirable for the purposes of operation.

In carrying out my invention, I provide a shunt path for the magnetic flux, preferably using a portion of .the frame of the relay for this purpose. I also provide means whereby the reluctance of the shunt path may be lvaried and the effective field strength thereby maintained more or less constant with different exciting currents.

In the accompanying drawing I .have shown one construction in which my inven` tion may be embodied. t 1

In thlspdrawing Figure 1 is an elevation, partly in section, of a relay provided with my lnvention; and Fig. 2'is a sectional plan view on line 2 2 of Fig. 1, the lower part of the relay being in shown in dotted lines.

eferring to the drawing, 5 indicates a base, preferably of insulating material, upon which the parts of the. relay are mounted. relay, the. form of drawings, may be means of screws 7 which is evident from the attached to the base 5 by Vtprassing through lu s whlch extend from the he coil which carries the ame as shown.

omitted and the operating coil bei,

motor current consists Aas 'shown of two straight terminals E5 and a middle U-shaped portion 9 which partially surrounds a fixed core 10 extendin downward from the top of ythe frame 6. T is core 1() has a threaded head 11- which screws into the frame and permits adjustment of the core 10 in' a vertical direction. The maintaining coil is shown at 12 mounted in the lower part `of theframe and insulated therefrom in any suitable manner. This coil may conveniently be made by windin it on a sheet metal s ool 12 between whic and the coil a layer o insulating material 18 is interposed. After the spool is slipped into the frame, a tube 14 of brass or other non-magnetic material forced up through the hole in the bottom of the frame will serve to kee it in place. The Vmovable element of the re ay may be of any suitable construction and, as shown, comprises an iron core 15 adapted to slide easily within the tube 14, said core havin' a guide pin 1 6 sliding into a hole in the fixe core 1.0,

27 and 28 W as shown in Fig. 1. Mounted loosely on the rod 17, which projects from the bottom of the core 15, is a contact disk 18. Above said disk 18, and secured to the rod 17 is a collar 19, and below the disk is a collar 20 also secured to the rod 17, a spring 21 being interposed between the disk 18 and collar 20.

Another contact disk 22 is loosely mounted on the rod 17 and is onl lifted when it is engaged by the nut or co ar 23 secured to the lower end of the rod 17. The contact disk 18, when the core is raised, connects fixed contacts 24 and 25. Contact 24 is connected to one end ofthe coil 12 and the other end of this coil is connected to a terminal 26. The lower contact disk 22, when the relay is in its lower 1plosition, bridges ixed contacts Y 'chare connected to terminals 29 and 30 through blow-out coils 31 and 32 in a usualand well known manner. It is at this set of contacts that the control circuit is interrupted.

I now come to the principal feature of my invention which is the shunt by which more or less ofthe magnetism produced by the coil 9 ma be shunted if the current which is to pass t ough the coil 9 is more than that necessary to produce the field strength'regquired for operation. This shunt is shown in Fig. 1 betweenthe coils 9 and 12. It com` prises an iron web 35 preferably integral with the frame 6, and a number of bushings 37, 38 and 39 which are arranged to nest one within the other and are su ported by the web 35. These bushings may be easily inserted if the core 10l is raised-or removed. The bushings may be secured in any suitable manner, as by frictional engagement with one another.

The operation of my relay is apparent from the drawing. The heavy coil 9 produces a magnetic field, which, when it reaches a certain stre h, draws up the movable core 15. The effective strength of the ield produced by the coil 9 may be reduced by the insertion o the bushings 37 38 and 39. These serve to lessen the air gap between the web 35 and the lower end of the core 10. As the air gap is decreased by the insertion of bus more iiux passes through this shunt path- 1nstead of by the path formed b the core 15 and the side memberson the ame 6. By removing successively the bushings 39, 38

and 37 the reluctance of the shunt path is increased, and the effective strength of the magnetic ield produced by the coil 9 is increased.' In this way the relay may be calibrated for high current values.

While I have shown you one form of apparatus in which my invention may be embodied, I wish it understood that-I do not intend to limit myself to this construction, but aim to c'over all such modifications as will occur to those skilled in this art.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. In a relay, a current carrying coil, a core movable 1n the ma netic ield thereof, a frame serving as a pat for the magnetic flux, and adjustable means coperating with said frame for shunting more or less of the flux around said core. v

2. In a relay, a current carrying Y coil, a core movable in the magnetic fie ereof, a

frame serving as a path for the flux andas a magnetic shunt around said core, and means for varying the reluctance of the shunt path.

3. In a relay, a current carr coil, a .core movable in the magnetic ie d t ereof, a

frame serving as a path for the lux and as a magnetic shunt around said core, and bushings for varying the reluctance of the shunt ath. p 4. In a relay, a current coil, a core movable in the magnetic fie d t ereof, a frame for su porting said core and serving as a path for t e ilux and as a magnetic shunt around said core, and bushings arra ed t0 nest one within the other for varying t e reluctance of the shunt path.

5. In a relay, a current carrying coil of few turns, a current carrying coil of many turns, a core movable in the field produced by'both coils, a'rame'for sup orting said core and serving as a path for t e flux, and an adjustable extension on said frame for shunting a portion of the flux of the first mentioned coil around'said core.

In Witness whereof, I have hereunto set my handthis 23rd day of August 1907.

ARCHIBALD S. CUBITT. Witnesses:

HEwLE'rr ScUDDER, Jr., HELEN ORFORD. 

